USEFUL TOOL FROM ZEUS

Zeus was father to the gods and the new Zeus assembler for the 48K Spectrum is the big daddy of all assembler programs. It is very simple to use for the beginner but for someone who has even a basic knowledge of the subject the program can be a powerful machine code tool.

The lines of assembly code are given line numbers so that it is possible to enter new lines or to alter old ones. There is an auto-line number routine in the program, which will prevent the user having to put in line numbers, and a re-number routine which will re-number the whole program or only part of it.

If errors occur during the assembly process the computer will list the errors with the line on which they occur. If there are no errors you can save the machine code and run it using a one-letter command "X".

Crystal Computing, the manufacturer of Zeus, also produces a monitor and disassembler for the Spectrum. As well as doing a full disassembly, the program will display the current state of the registers and alter them if necessary. It will also substitute lines of code and move around blocks of memory.

The Zeus asembler and the monitor and disassembler have been sadly neglected in the past. Both packages can be used together and form a very powerful tool. Zeus costs £8.95 and the disassembler and monitor cost £8.95. Both packages can be obtained from Crystal Computing, 2 Ashton Way, East Herrington, Sunderland SR3 3RX.

THE EASIER ROUTE FROM BASIC TO MACHINE CODE

Writing programs is time-consuming. John Gilbert examines a collection of cassettes which help to make the job much simpler.

The best way to learn about machine code is to use an assembler. Machine code consists of numbers but with an assembler the user can write code in assembler language, which looks more like Basic and is easier to understand. The program will then convert the user's assembly language instructions, called source code, into machine code.

Although the ZX-81 has been around for several years there are only a few machine code assemblers available on the market for it. The only big companies to produce assemblers for the machine are Artic Computing and Bug Byte. Both built their reputations with these assemblers.

The Artic assembler is a two-pass program. It will permit full use of labels, will inspect and modify registers and also allows output to a printer. The code to be assembled is put into a REM statement at the beginning of the program and all code can be written in standard Z-80 mnemonics. The assembler will also assemble messages which are to be used in programs into hexadecimal code. It costs £9.95.

The other best-seller is the Bug-Byte ZXAS. The program is similar to that of Artic but was launched in a blaze of publicity as being the first machine code assembler for the ZX-81.

Bug-Byte also wanted to be the company which produced the first assembler for the Spectrum but it was to be disappointed. Wrangling within the company between its programmers put the release date further and further back until the package became available early this year.

The program is for the 16K and 48K Spectrum. It is very comprehensive in its options and very easy to use. As well as assembling user machine code, it has a full editor facility with which the user can view assembly code, delete and insert, search for specific strings of text within machine code, and list all the labels which have been specified by a user in a program within a cross-referenced table.

The editor will also reverse 16-bit values, such as memory addresses, if the user specifies that option. That facility is useful when dealing with a large number of 16-bit addresses in a long program. The use of 16-bit values can be a problem for beginners, who often do not know whether or not to reverse a number.

The program also has a good cassette interface. Both the source code - the user's - and the object code - assembled-code can be filed on to cassette. That means that source code can be saved and re-edited when the user needs it. The saved source code could also be useful if the programmer wanted to upgrade a program.

Unfortunately the manual, or lack of it, provides points against Aspect. Instructions are written on a piece of paper. They are just about adequate and contain no examples. Aspect costs £9 and is available from shops such as W H Smith.

Picturesque slipped its Editor/Assembler on to the market very quietly. The program is for the 16K and 48K Spectrum and is very powerful. It is complete with a comprehensive user manual which a complete beginner can understand.

The Editor is the part of the program which enters the source code. It is possible to enter code in the same type of format as a Basic program, as each line is given a line number. Unlike the Basic system on the Spectrum, line numbers can be generated by the program automatically with the use of the AUTO command. The use of line numbers means that the source file can be edited quickly and easily.

When the source code has been entered correctly and there are no bugs in the text, the assembler can be called into operation. The usual ORG instruction is included as part of the instruction set to define the address at which the assembled code should be put.

The program display is interesting, as the screen has a 40-column width and is split into several fields which correspond to those used in assembly language programming, together with a line number field. The cursor recognises the end of one field and jumps to the next automatically. That makes the entered source code easy to understand. The Editor/Assembler is ideal for the beginner and could also be a powerful tool in the hands of a professional programmer. It costs £8.50.

The program which has caused a buzz of excitement in the Sinclair User offices is probably one of the most powerful assemblers which we have reviewed. It is all the more remarkable as it is produced by a small and, until now, largely unrecognised software house, Crystal Computing.

The program, Zeus, is a two-pass assembler which allows the use of the full Z-80 mnemonic instruction set. Source code can be line-numbered and an AUTO line-number facility is also available.

The program is accompanied by the best manual we have seen for an assembler. It contains step-by-step instructions for entering and editing source code. An example is included which will, if entered correctly, colour the screen white, the current ink colour.

The use of an example in that way is good, because if you make a mistake and the program does not work you will have to re-learn the instructions. If the example works, users will have a good understanding of how Zeus operates.

Zeus also contains several subroutines which can be used within source code. They include an INKEY$-type function and print a character routine. Other functions in the assembler include automatic re-numbering of the source file, outputting of code to a printer, and the reclaiming of 'old' source files for further work. Zeus has been aptly-named by Crystal Computing. It costs £8.95.

There are very few good assemblers on the market although the big software houses all claim to have the best available. It is, therefore, surprising that a small company like Crystal should produce such an excellent assembler as Zeus. The reason may be that while large companies spend their money on colourful advertising, smaller companies need to rely on very good quality products.

Artic Computing, 396 James Reckitt Ave, Hull, North Humbersade HU8 0JA.

Picturesque, 6 Corkscrew Hill, West Wickham, Kent BR4 9BB.

Crystal Computing, 2 Aston Way, East Herrington, Sunderland SR3 3RX.

NEW COMPANIES ON THE SINCLAIR BANDWAGON

John Gilbert looks at the latest additions to Sinclair Research's growing software library.

Sinclair Research seems to have its eye on the rest of the software market, something which it was loathe to do two months ago. It has opened its software range to such an extent that new and smaller companies, other than Artic Computing and Melbourne House, have had a chance to enter their programs into a range which already includes such programs as The Hobbit and the Artic range of adventures.

The new companies on the Sinclair Research bandwagon are Crystal Computing and Ultimate Play The Game. Crystal Computing has sold its Zeus Assembler and Monitor Disassembler to Sinclair. That means it at last has two machine code utilities, for the 48K Spectrum, in its range.

The Crystal Zeus Assembler is one of the best of its kind and provides excellent facilities for beginners and experts alike. Writing assembly language using it is almost as easy as writing Basic code. Each line of source assembly code as indexed with a number, just as Basic instructions are indexed with line numbers.

All the features which are found usually on assemblers have been included. Labels and expressions can be included within source code and strings of symbols can be entered into memory tables using the utilities in Zeus.

One of the advantages of Zeus is that you do not have to include an ORG instruction with the program to indicate to the computer where to put the object code when it has been assembled. If you omit the ORG instruction the computer will allocate the code to a space in memory.

The problem with Zeus is that you have to exit from the assembler to save the code which has been generated. If you are a beginner that can be a lengthy and nerve-racking process and you have no guarantee that you can load the code back into the computer.

Apart from the lengthy preparations for loading and saving, the assembler is still one of the best on the market. It is a pity that Sinclair Research has put it into a colourful box to justify a price rise of approximately £4. The box may look pleasant and it may improve the quality of the product on the shelf, from a commercial point of view, but the box will not help you to program.

The same is true of many of the other programs in the range. The boxes do not add anything to the product once you have it at home and paying up to £4 extra for packaging is unlikely to go down well with most customers.

The Monitor and Disassembler for the 16K/48K Spectrum is from Crystal and the price of the product has also been increased substantially. It can be used with the Zeus Assembler and will provide a disassembly of source code from your machine code programs or from the Spectrum operating system in the ROM of the machine.

The Monitor will also enable the user to assign values to the CPU registers. That means that values can be set to test machine code programs and to see how they run under certain conditions. Machine code routines can be copied from one part of memory to another and the routines can be edited in hexidecimal using the Monitor. One other useful function is to convert a hexidecimal value to decimal and vice versa when you are using the editing routines. That saves a number of calculations on paper.

The Monitor and Disassembler is the perfect companion to the Assembler but at a combined price of nearly £25 it is expensive.

The next two additions to the Sinclair software library for the Spectrum can both be regarded as mind games. Flippit, for the 16K or 48K Spectrum, has been put on a parallel with the Rubik Cube by Sinclair Research. It certainly is a maddening puzzle and almost impossible to master completely. The Flippit board is like a noughts and crosses grid - it has nine sectors, set out in a three-by-three grid. The computer labels those using the letters the alphabet, A to I, and numbers or dots fill each corner of each square.

To complete the game you must find the correct combination of numbers so that they add to the same sum horizontally, vertically and diagonally. That means the game is nothing more than the type of magic squares we all enjoyed solving when we were at school.

They can be played competitively and to emphasise the point the moves you have taken so far and the moves which you have to beat before getting the record are part of the board display.

There are three playing options. The first is New Run which will make the computer re-shuffle the numbers on the board into random patterns. The next option is similar to the first and will re-run the last random setting. That means that the order in which the numbers were placed on the last shuffle is restored.

Flippit seems so easy when you first start to play but when you have only two numbers out of place it can become irritating and it is easy to give up, rather than plodding along with the problem. If you are left with the numbers in the wrong places you may have to do major re-shuffle of the board.

The manual is concise and to the point but includes no information about strategy or play. It tells the player only how to set up the Spectrum and what are the various play options.

One other criticism is that it has no SAVE option for beginners who are puzzlers or who want to break for lunch.

The other mind game in the selection is more of a test of mind power. The Cattell IQ Test provides the user with a standard reference to any intelligence quotient. It is the type of test which potential members of Mensa, the organisation whose members have high IQs, must take.

On loading, the computer takes some time to set up the tests. There are six types of logic test which must be taken before the computer can give you an accurate IQ score. Those types include synonym finding, classification, opposites, analogies and inferences.

The results are co-ordinated from the various individual tests to give a percentile overall rating. The Spectrum will tell you eventually whether it is worthwhile applying for membership of Mensa.

After being extremely serious about the validity of the tests, throughout the manual it says in the section about the meaning of the results that the tests should not be taken too seriously and that the tests will not prove that you are a genius. Even if you cannot go around wearing a badge saying 'genius', once you have taken the Cattell test you should have some fun with the package.

Unfortunately the copy we were sent of the rests was tediously slow in producing marks for the various sections and in setting-up the data. Although it looked like a production copy of the package, Sinclair Research says that it is producing a better version of the program.

The final cassette-based program from the library, for the 48K Spectrum, is Chequered Flag and it is the only one not in a box. The program is from Psion and it is up to that company's usual standards.

The game sets you as a racing driver over one of the number of world-famous racing tracks, such as Silverstone. You can choose which car you want to use from a visual menu describing a number of well-known racing cars. You can also choose the course on which you want to travel.

The race will take place on the screen, using a three-dimensional representation of the track. Apart from the danger of crashing over the sides of the track, there is also oil on the road surface. At all costs you must avoid the oil or it could cause your car to skid. Once you have been round the track the required number of times, the chequered flag will be raised on the screen and your lap time will be given by the computer.

The graphic and real-time simulation effects produced by the software are reminiscent of the Flight Simulation program, also available from Psion through Sinclair Research. There are several tracks and cars to try, so the game should provide hours of entertainment. The quality of the game and the detail included make it one of the great games for the Spectrum.

The quality control and selection of software for the Sinclair software library has certainly increased with the release of this new batch of tapes. The boxes in which most of the products are now packaged are certainly an improvement on the cassette covers which were being used. One disadvantage for retailers will be that display shelves will be occupied more quickly by fewer products. That should be offset, though, by the prices which Sinclair is charging for its new software.

That has already caused murmurs of discontent from customers about to buy software from a company, only to find that Sinclair has bought it and the price has been increased. If Sinclair continues to raise its prices in this way the company could sell less in the way of software and customers may go elsewhere in a large market. That would be a bad move.

The 'L' Game is produced by Quicksilva. It consists of some coloured tiles on a board which are originally in the shape of an 'L' but which the computer manages to mix extremely well. The player then has to slide the tiles back into the correct order to form the 'L' in the least number of moves. It is like doing a jigsaw puzzle with no edges.

Also included on the cassette with the 'L' Game are Mastermind and Pontoon. If you like puzzles, this cassette is good value for money.

Flippit is from Sinclair Research and is a test of logic and arithmetic. The player has to get all the numbers or dots in a square in such a position that the values will be the same when added horizontally, vertically and diagonally. It is a puzzle which you will either love or hate.

The game is like a giant magic square and if you are adept at spotting combinations and have a fast calculation rate you should be able to do the puzzle fairly quickly. So far I have managed to fit the puzzle together with only two pieces remaining out of sequence. The problem is that the instructions are not so good as the puzzle and you could have difficulty in getting started.

Flippit is suited to those people who like IQ tests to learn their so-called intelligence quotient. I think that the only thing IQ tests prove is that a person can do an IQ test but if you want to learn what your rating is you might like to try The Cattell IQ Test.

I would be interested to hear your views on this or any other IQ test and also the marks you gained. Do not cheat. The Spectrum is ideally suited to such an application but is the application valid.

I hope that I have provided you with some ideas about the mind games on the market, especially those suitable as Christmas presents. You should not have too much difficulty deciding what to buy even though there is a wide area to cover.

Melbourne House, 131 Trafalgar Road, Greenwich, London, SE10 - The Hobbit

Carnell Software, North Weylands Industrial Estate, Molesey, Hersham, Surrey, KT12 3PL - Volcanic Dungeon, Black Crystal, The Wrath of Magra

Sinclair Research, Freepost, Camberley, Surrey GU15 3BR - Artic Adventures A, B, C, D, Flippit

Quicksilva, 55 Haviland Road, Ferndown Industrial Estate, Wimborne, Dorset - 'L' Game.

THE EASIER ROUTE FROM BASIC TO MACHINE CODE

Writing programs is time-consuming. John Gilbert examines a collection of cassettes which help to make the job much simpler.

The best way to learn about machine code is to use an assembler. Machine code consists of numbers but with an assembler the user can write code in assembler language, which looks more like Basic and is easier to understand. The program will then convert the user's assembly language instructions, called source code, into machine code.

Although the ZX-81 has been around for several years there are only a few machine code assemblers available on the market for it. The only big companies to produce assemblers for the machine are Artic Computing and Bug-Byte. Both built their reputations with these assemblers.

The Artic assembler is a two-pass program. It will permit full use of labels, will inspect and modify registers and also allows output to a printer. The code to be assembled is put into a REM Statement at the beginning of the program and all code can be written in standard Z-80 mnemonics. The assembler will also assemble messages which are to be used in programs into hexadecimal code. It costs £9.95.

The other best-seller is the BugByte ZXAS. The program is similar to that of Artic but was launched in a blaze of publicity as being the first machine code assembler for the ZX-81.

Bug-Byte also wanted to be the company which produced the first assembler for the Spectrum but it was to be disappointed. Wrangling within the company between its programmers put the release date further and further back until the package became available early in 1983.

The program is for the 16K and 48K Spectrum. It is very comprehensive in its options and very easy to use. As well as assembling user machine code, it has a full editor facility with which the user can view assembly code, delete and insert, search for specific strings of text within machine code, and list all the labels which have been specified by a user in a program within a cross-referenced table.

The editor will also reverse 16-bit values, such as memory addresses, if the user specifies that option. That facility is useful when dealing with a large number of 16-bit addresses in a long program. The use of 16-bit values can be a problem for beginners, who often do not know whether or not to reverse a number.

The program also has a good cassette interface. Both the source code - the user's - and the object code - assembled-code can be filed on to cassette. That means that source code can be saved and re-edited when the user needs it. The saved source code could also be useful if the programmer wanted to upgrade a program.

Unfortunately the manual, or lack of it, provides points against Aspect. Instructions are written on a piece of paper. They are just about adequate and contain no examples. Aspect costs £9 and is available from shops such as W H Smith.

Picturesque slipped its Editor/Assembler on to the market very quietly. The program is for the 16K and 48K Spectrum and is very powerful. It is complete with a comprehensive user manual which a complete beginner can understand.

The Editor is the part of the program which enters the source code. It is possible to enter code in the same type of format as a Basic program, as each line is given a line number. Unlike the Basic system on the Spectrum, line numbers can be generated by the program automatically with the use of the AUTO command. The use of line numbers means that the source file can be edited quickly and easily.

When the source code has been entered correctly and there are no bugs in the text, the assembler can be called into operation. The usual ORG instruction is included as part of the instruction set to define the address at which the assembled code should be put.

The program display is interesting, as the screen has a 40-column width and is split into several fields which correspond to those used in assembly language programming, together with a line number field. The cursor recognises the end of one field and jumps to the next automatically. That makes the entered source code easy to understand.

The Editor/Assembler is ideal for the beginner and could also be a powerful tool in the hands of a professional programmer. It costs £8.50.

The program which caused a buzz of excitement in the Sinclair User offices is probably one of the most powerful assemblers which we have reviewed. It is all the more remarkable as it is produced by a small and, until now, largely unrecognised software house, Crystal Computing.

The program, Zeus, is a two-pass assembler which allows the use of the full Z-80 mnemonic instruction set. Source code can be line-numbered and an AUTO line-number facility is also available. The program is accompanied by the best manual we have seen for an assembler. It contains step-by-step instructions for entering and editing source code. An example is included which will, if entered correctly, colour the screen white, the current ink colour.

The use of an example in that way is good, because if you make a mistake and the program does not work you will have to re-learn the instructions. If the example works, users will have a good understanding of how Zeus operates.

Zeus also contains several subroutines which can be used within source code. They include an INKEY$-type function and print a character routine. Other functions in the assembler include automatic re-numbering of the source file, outputting of code to a printer, and the reclaiming of 'old'source files for further work. Zeus has been aptly-named by Crystal Computing. It costs £8.95.

There are very few good assemblers on the market although the big software houses all claim to have the best available. It is, therefore, surprising that a small company like Crystal should produce such an excellent assembler as Zeus. The reason may be that while large companies spend their money on colourful advertising, smaller companies need to rely on very good-quality products.

Artic Computing, 396 James Reckitt Avenue, Hull, North Humberside HU8 0JA.

Picturesque, 6 Corkscrew Hill, West Wickham, Kent BR4 9BB.

Crystal Computing, 2 Aston Way, East Herrington, Sunderland SR3 3RX.